The rising cost of homes and the ever-decreasing supply of building lots has sparked a marked increase in the remodeling of existing homes. Remodeling to expand the existing structure and gain additional space is often less expensive and easier than selling an existing home and buying a new one. Given the small size of many center city and suburban building lots, expansion may only proceed in one direction: upwards.
Constructing another level to the existing building is generally accomplished by removing and discarding the existing roof, and building new walls, floor, and roof over the existing building. Alternatively, a roof may be severed from the building and a crane brought in to remove the roof while the building is enlarged. The roof is later reinstalled and reattached on top of the new structure.
The feasibility of using a crane, however, is limited to larger yards which will accommodate the larger cranes needed to lift the weight of a roof. Many roofs, in fact, may be too heavy for even a large crane to lift. Even if the roof can be lifted by the crane, the yard must be large enough to enable the crane to get near the building as well as for the crane operator to set down the roof section, once severed from the existing building, while the new structure is being built. An added concern is that the existing structure can be damaged by adverse weather conditions occurring while the roof is removed. Further, severe damage to the building owner's yard and landscaping is often caused by the large crane itself, as well as the roof stored in the yard.